Poking at China is like poking at a dragon. You will inevitably just bring wrath down upon you.

China clearly does not respond to foreign pressure regarding the Tibetan issue. No country will stand up for the Tibetans. Trade is worth more than the welfare of Tibetans to China's trading partners, which nowadays includes the whole world more or less.

When you are at such a huge disadvantage your only option really is to negotiate with your superiors on their terms.